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PubMed2003

Statistical mechanics of broadcast channels using low-density parity-check codes.

We investigate the use of Gallager's low-density parity-check (LDPC) codes in a degraded broadcast channel, one of the fundamental models in network information theory. Combining linear codes is a standard technique in practical network communication schemes and is known to provide better performance than simple time sharing methods when algebraic codes are used. The statistical physics based analysis shows that the practical performance of the suggested method, achieved by employing the belief propagation algorithm, is superior to that of LDPC based time sharing codes while the best performance, when received transmissions are optimally decoded, is bounded by the time sharing limit.

Journal Article↗

PubMed2004

Improving the precision of the keyword-matching pornographic text filtering method using a hybrid model.

With the flooding of pornographic information on the Internet, how to keep people away from that offensive information is becoming one of the most important research areas in network information security. Some applications which can block or filter such information are used. Approaches in those systems can be roughly classified into two kinds: metadata based and content based. With the development of distributed technologies, content based filtering technologies will play a more and more important role in filtering systems. Keyword matching is a content based method used widely in harmful text filtering. Experiments to evaluate the recall and precision of the method showed that the precision of the method is not satisfactory, though the recall of the method is rather high. According to the results, a new pornographic text filtering model based on reconfirming is put forward. Experiments showed that the model is practical, has less loss of recall than the single keyword matching method, and has higher precision.

Algorithms↗

PubMedDate not supplied

Angina and socio-economic status in Ontario: how do characteristics of the county you live in influence your chance of developing heart disease?

OBJECTIVE: To assist in the development of community heart health programming and policy development, the Central West Health Planning Information Network (CWHPIN) was asked by its partners to collaborate in obtaining information that might clarify the relationships between socio-economic status (SES) and heart disease among residents of Ontario, Canada. The purpose of this component of the project was to explore, at the county level, how much of the variation in angina pectoris (angina) could be explained by SES variables. STUDY DESIGN: Linear regression modeling was used to identify key predictors of angina hospitalization rates in counties Ontario-wide. RESULTS: Results of the linear regression modeling showed that SES variables (most notably education and occupation) were key predictors of angina, even when traditional risk factors (i.e., smoking, etc.) were included in the analysis. CONCLUSION: This study demonstrates that, at the county level, socio-economic variables such as education and occupation have a significant relationship with rates of heart disease at the population level, even when including the traditional risk factors in the analysis.

Adult↗

PubMed1991

Using comparative clinical information to understand practice patterns and affect organizational change.

The University Hospital Consortium is collecting clinical, administrative and financial data from its members to develop a Clinical Information Network. The value of this collective data lies in how comparative information about peer hospitals and physicians in the same specialty can be used to influence practice. The raw data from each hospital is analyzed, classified, normalized and stored in a data repository which is easily accessible. This data becomes information when it is presented in a variety of ways, and is supported by a knowledge-base of health care rules. The "drilling down" technique to progressive levels of detail serves the needs of all levels in the organization--executives, managers, and analysts. The system combines the power of a mainframe for the data repository with the ease of use of a PC-based workstation. With an open-ended approach, the users can ask a variety of questions of the data, as well as perform statistical analysis, create graphical presentations and generate explanations of the analysis techniques.

Artificial Intelligence↗

PubMedDate not supplied

Injuries from vascular access devices: high risk and preventable. Collaborative EPINet Surveillance Group.

Intravenous catheter stylets are the number one cause of needlesticks from blood-filled needles, the type of injury that is most likely to transmit bloodborne pathogens. The Exposure Prevention Information Network (EPINet, a trademark of the University of Virginia) database provides information on the characteristics of injuries from i.v. catheter stylets and on the effectiveness of safety i.v. catheters designed to prevent injuries. EPINet data show that nurses sustained three fourths of these injuries, and that injury rates declined by 84% after the introduction of a safety i.v. catheter in three study hospitals. In order to reduce the risk of bloodborne pathogen transmission to healthcare workers, especially nurses, the widespread implementation of i.v. catheters designed to prevent needlesticks should be undertaken as quickly as possible.

Catheters, Indwelling↗

PubMed2006

[Military telemedicine: a network of networks].

Military telemedicine is a form of collaborative medicine based on the use of communication and information networks. It is more a network of networks than of independent systems. It comprises electronic medical files, epidemiological networks, and surgical and medical databases. Each system must be able to communicate with the others, thereby enabling the development of remote consultation, expertise and assistance. This requires networking between the army, the navy, and the air force communication networks, especially during special operations conducted abroad. We must also develop interoperability with systems in other countries, and with the French civilian health service. This means respecting the general rules governing these networks. The military health network is unique, in that it focuses on battlefield injuries. In addition, the French military health service operates under a single headquarters, governing nurses, paramedics and physicians.

Military Medicine↗

PubMed1994

Combining evolutionary information and neural networks to predict protein secondary structure.

Using evolutionary information contained in multiple sequence alignments as input to neural networks, secondary structure can be predicted at significantly increased accuracy. Here, we extend our previous three-level system of neural networks by using additional input information derived from multiple alignments. Using a position-specific conservation weight as part of the input increases performance. Using the number of insertions and deletions reduces the tendency for overprediction and increases overall accuracy. Addition of the global amino acid content yields a further improvement, mainly in predicting structural class. The final network system has sustained overall accuracy of 71.6% in a multiple cross-validation test on 126 unique protein chains. A test on a new set of 124 recently solved protein structures that have no significant sequence similarity to the learning set confirms the high level of accuracy. The average cross-validated accuracy for all 250 sequence-unique chains is above 72%. Using various data sets, the method is compared to alternative prediction methods, some of which also use multiple alignments: the performance advantage of the network system is at least 6 percentage points in three-state accuracy. In addition, the network estimates secondary structure content from multiple sequence alignments about as well as circular dichroism spectroscopy on a single protein and classifies 75% of the 250 proteins correctly into one of four protein structural classes. Of particular practical importance is the definition of a position-specific reliability index. For 40% of all residues the method has a sustained three-state accuracy of 88%, as high as the overall average for homology modelling. A further strength of the method is greatly increased accuracy in predicting the placement of secondary structure segments.

Amino Acid Sequence↗

PubMed2006

A participatory assessment of IS integration needs in maternity clinics using activity theory.

The design and development of information systems should focus on a wider context than merely one user group or organization. This is particularly the case with systems integration. A tentative description of the activity network, information needs, and user requirements should be acquired before any major changes are planned. Relatively rapid yet participatory methods are needed at this preliminary stage. In this article, we claim that activity theory offers a suitable framework for this. Subsequently, we present a qualitative study in which this approach was used, with focus on the practices of the information management within a maternity care activity network. The first aim was to elicit the most important integration needs in the existing information systems of Finnish maternity clinics. Secondly, we wanted to introduce a participatory approach to be utilized by the service-providing organizations themselves, rather than software companies or quality consultants. Data were collected in multi-professional group interviews. The results include information needs and communication problems as well as outlines for solutions in the systems integration of maternity clinics. Various tools of information management do not meet the concrete needs of health care work. Integration is needed on many levels, and it has to be adapted to the needs of numerous stakeholders. The applied activity-theoretical framework proved useful in describing such a multi-faceted system of information and its users. More research is needed on its wider applicability, particularly in situations where researchers are not active participants.

Access to Information↗

PubMed2000

Poppies in a wheat field: exploring the lives of rural lesbians.

Many believe that lesbian identity is predicated upon the availability of opportunities in urban life to find information, support, and like others (Bell and Valentine 1995a). Indeed, exploring one's lesbian sense of self often involves identifying with a visible reference group, seeking out social arenas where there are other gays and lesbians, connecting with a local community, and taking part in gay and lesbian oriented activities. For rural residents, these opportunities are mostly unavailable, and the lack of access to information, to a public meeting space, and to connections with other lesbians further hinders the development of social group identity. Given that gay and lesbian identity has as its basis a social reference group, how might rural lesbians develop and sustain their sense of personal and group lesbian identity? With few exceptions (D'Augelli 1989; D'Augelli et al. 1987; Kramer 1995; Krieger 1982) the empirical research conducted on the lives of gays and lesbians has utilized urban and suburban samples. Likewise, research on rural life has omitted the experiences of gay and lesbian residents. Either way, information about rural lesbian life remains mostly uncovered. This pilot study attempts to provide new information about the experiences of rural lesbians. Utilizing focus group interviews, the challenges of sustaining lesbian identity in a rural setting are explored. The data show that for this sample, although rural lesbians initially felt isolated and unsure of how to develop a sense of group identity, the opportunity to connect with a small informal network of friends and acquaintances helped alleviate these problems. Further, because these women have little access to information, public gathering space, or to local gay culture, this network was said to be crucial. Without it, the women feel invisible and isolated, that is, their identity remains unseen.

Adolescent↗

PubMed1993

Protection of patient data in multi-institutional medical computer networks: regulatory effectiveness analysis.

Privacy protection is one of the major issues in the development of multi-institutional clinical information networks. Judicial decisions have confirmed patient's rights to protection of a "reasonable expectation of privacy". Incorporating this protection into a system requires analysis of appropriate models. The National Practitioner Data Bank (NPDB) contains confidential data concerning physician competence. The medical profession had substantial input into the privacy protection features of the NPDB, which are much more comprehensive than those used in many clinical information systems. The NPDB represents the privacy protection which physicians expect for their own data. Regulatory Effectiveness Analysis can be used to analyze the suitability of the NPDB as a model for patient privacy protection. Judicial opinions set public policy and legal structures for privacy, and the NPDB provides an inventory of useable technical tools. After eliminating minor discontinuities, the NPDB can be used as a model to create a useable standard for privacy for multi institutional data transfers.

Civil Rights↗

PubMed1997

Health On the Net automated database of health and medical information.

With the number of World Wide Web sites growing every day, the problem is not just to find information, but to locate the right piece of information. Current World Wide Web search engines have not resolved this problem as they most often return a long list of documents. The search result is then unusable because of the large number of answers from different domains and topics. Only complex queries may, in a given situation, produce a limited number of potentially relevant documents. To make searches more efficient and usable by common users, we now need intelligent and specialised search engines on the Net [1,2]. Health On the Net Foundation and the Molecular Imaging and Bioinformatics Laboratory at Geneva University Hospital have developed Multi-Agent Retrieval Vagabond on Information Networks (MARVIN), a robot that searches sites and documents specifically related to a given specialised field. One such robot has already been implemented and used for the medical and the 2D electrophoresis domains. Health On the Net Foundation has implemented the corresponding search engines, MedHunt (http://www.hon.ch/cgi-bin/find) for the medical field and 2DHunt (http://www.hon.ch/cgi-bin/2DHunt/find) for the 2D electrophoresis field.

Computer Communication Networks↗

PubMed1998

HIV/AIDS patients' perspectives on adhering to regimens containing protease inhibitors.

OBJECTIVE: To gather qualitative data regarding HIV/AIDS patients' perspectives about HIV-1 protease inhibitors (PIs), and about their experiences taking and adhering to regimens containing PIs. DESIGN: Six focus groups of persons under care for HIV were conducted between September and November 1996 regarding participants' knowledge, awareness, experiences when taking, and adherence to antiretroviral regimens containing PIs. An identical discussion guide was used to facilitate all six groups. Focus group proceedings were audiotaped, transcribed, coded for themes, and analyzed qualitatively. SETTING: HIV/AIDS practices of three teaching hospitals and two community health centers. PATIENTS/PARTICIPANTS: Fifty-six patients with HIV disease: 28 men and 28 women. MEASUREMENTS AND MAIN RESULTS: Knowledge and positive impressions of PIs were prevalent among this diverse group of persons with HIV, and did not differ by race/ethnicity or gender. Most knew that these were new, potent medications for treating HIV/AIDS. Networks of persons with HIV and medical providers were the most important information sources. Those taking PIs were aware that adherence to the regimen is important, and most were using special strategies to maximize their own adherence, but expressed considerable frustration about the central role these medication regimens had assumed in their life. A subset who did not believe they would adhere to these regimens had declined treatment with them. Motivating factors for taking and adhering to these complex regimens were improving CD4 counts and viral loads and the patient-provider relationship. CONCLUSIONS: Among those with HIV/AIDS, awareness of PIs and their effectiveness is substantial, owing to the impact of informal networks and medical providers. This early positive "reputation" of PIs may enhance motivation for adherence. Those who are taking PIs invest substantial effort adhering to these complex regimens, but resent the need to make medications the focus of their lives.

Adult↗

PubMed2006

Configurations of informal social support among older lesbians.

Limited research has been conducted on the needs and concerns of older lesbians in the American population. The purpose of this paper is to present findings from a qualitative study of older (aged 55 and older) lesbians' experiences of and perspectives on aging, with a focus on their discussions of social support. Through an in-depth qualitative study with 25 older lesbians, we found that aging lesbians may be less likely to access formal social services due to perceptions of bias within the services and a potential lack of connection with those who do use services. However, participants were creative at formulating informal networks of support. Four heuristic categories (empowered, secure, independent, and precarious) of informal social support were developed to characterize the various ways in which participants configured their support systems. Social support within each category was conceptualized both in terms of intentionality and degree of connectedness. Being partnered did not necessarily equate with a strong sense of social support. Further research needs to be conducted on older lesbians in order to better characterize and respond to their needs as they age.

Aged↗

PubMed1995

Info systems refocus priorities.

Healthcare executives say improving their computer systems' managed-care capabilities is their No. 1 information technology priority. Resolving thorny cost and control issues involving community health information networks also rated high among the executives.

Attitude of Health Personnel↗

PubMed1994

Health Data Management innovators 1994.

Throughout the country, innovative organizations are devising groundbreaking technology applications to cut administrative costs and improve the quality of care. For example, they are using EDI to eliminate paperwork and creating computerized patient records as the building blocks for health information networks. Health Data Management has singled out five organizations that are at the forefront in the application of automation. These include two provider groups, two payers and a research institute.

Computer Communication Networks↗

PubMed2000

High speed digital circuits for medical communication; the MINCS-UH project.

In Japan, a high speed, bidirectional digital satellite communication system called Medical Information Network by Communications Satellite for University Hospitals is currently available in 30 national universities, and many programs, including clinical conferences, lectures and tutorials, have been broadcasted. Its characteristics are: (1) a state-of-the-art digital high-definition television system, (2) excellent security protection using digital encryption (3) bidirectional communications using two satellite circuits simultaneously, and (4) easy operability. High-quality motion images, and security protection mechanisms are essential for use in clinical medicine.

Computer Communication Networks↗

PubMed2001

Upper bound of the expected training error of neural network regression for a Gaussian noise sequence.

In neural network regression problems, often referred to as additive noise models, NIC (Network Information Criterion) has been proposed as a general model selection criterion to determine the optimal network size with high generalization performance. Although NIC has been derived using asymptotic expansion, it has been pointed out that this technique cannot be applied under the assumption that a target function is in a family of assumed networks and the family is not minimal for representing the target true function, i.e. the overrealizable case, in which NIC reduces to the well-known AIC (Akaike Information Criterion) and others depending on a loss function. Because NIC is the unbiased estimator of generalization error based on training error, it is required to derive the expectations of errors for neural networks for such cases. This paper gives upper bounds of the expectations of training errors with respect to the distribution of training data, which we call the expected training error, for some types of networks under the squared error loss. In the overrealizable case, because the errors are determined by fitting properties of networks to noise components, including in data, the target set of data is taken to be a Gaussian noise sequence. For radial basis function networks and 3-layered neural networks with bell shaped activation function in the hidden layer, the expected training error is bounded above by sigma2* - 2nsigma2*logT/T, where sigma2* is the variance of noise, n is the number of basis functions or the number of hidden units and T is the number of data. Furthermore, for 3-layered neural networks with sigmoidal activation function in the hidden layer, we obtained the upper bound of sigma2* - O(log T/T) when n > 2. If the number of data is large enough, these bounds of the expected training error are smaller than sigma2* - N(n)sigma2*/T as evaluated in NIC, where N(n) is the number of all network parameters.

Analysis of Variance↗

PubMed1997

Medical computing in Mississippi.

As our society enters the information age, physicians are finding an ever growing role for computers in the practice of medicine. Computers are used for education, research, medical record keeping, communications and as a powerful reference resource. They have even served as electronic consultants to assist in diagnosis and medical decision making. Mississippians have been pioneers in the use of computers in research and education and have taken a very progressive view of the future of medical computing in our state. Resources such as the Mississippi Health Sciences Information Network have served to connect rural health practitioners to academic centers and other informational resources and improve the quality of patient care throughout the state. Internet users will find that there are many Mississippi medical institutions that have home pages on the world wide web that also connects us to the global medical community. Computers are rapidly becoming one of the most important new tools in the black bag of the modern physician.

Computer Communication Networks↗